Effect of feeding pre-L-methionine on high-cell-density fermentation for S-adenosyl-L-methionine production / 生物工程学报

The yield of S-adenosyl-L-methionine (SAM) by saccharomyces cerevisiae fermentation was affected by the strategy of feeding L-methionine. The effects that feeding strategies and the amount of precursor L-methionine had on the production of SAM by saccharomyces cerevisiae G14 were investigated. The results showed that feeding L-methionine could obviously improve the accumulation of SAM, and both the biomass and SAM yield relied heavily on different feeding strategies. In our work, it was found that total amount of L-methionine added should be no less than 0.7g per 10 grams of dry cell weight. Five different feeding strategies had been investigated in our experiment, and such comparison indicated that favorable results could be achieved as the biomass reached the status of high cell density (120g/L). If 9 grams of the precursor L-methionine was introduced once and for all, the accumulation of SAM reached maximum of 4.31g/L at the 18th hour after addition; if the precursor amino acid was fed at a rate of 2g/h in 5 h, maximum yield of 4.98g/L was achieved at the 28th hour after feeding. Thus high cell density fermentation can be successfully applied to SAM production by Saccharomyces cerevisiae with the consequence of over 130g/L of biomass gained using the above two strategies.

Optimal Study on the Fermentation Conditions of S-adenosyl-L-methionine / 微生物学通报

This paper focuses mainly on the study of optimal fermentation conditions of S-adenosyl-L-methionine.Effects of carbon sources,nitrogen sources,inorganic constituents,growth factors and adding time of L-methionine on the yield,the content and biomass of S-adenosyl-L-methionine are studied.And ingredients of the culture medium are also optimized by the method of uniform design.The final optimum culture medium contains: glucose 30 g,Yeast powder 11 g,(NH_4)_2SO_4 12 g,K_2HPO_4?3H_2O 5 g,KH_2PO_4 10 g,MnSO_4?H_2O 0.09 g,ZnSO_4?7H_2O 0.14 g,MgCl_20.5 g,CaCl_2 0.3 g,CuSO_4 0.005 g per liter. Using that optimum culture medium,the yield of S-adenosyl-L-methionine can reach 0.9 g/L in Erlenmeyer flask which is 30 % higher than before.Experiment on 5 L fermenter reveals that the accumulation of S-adenosyl-L-methionine can reach 2.66 g/L.Biomass is 23.4 g/L.